1. Field of the Invention
The present invention relates generally to starters for internal combustion engines, and more particularly to a starter having an intermediate gear adapted to remain in meshing engagement with a pinion gear at all times and operative to be brought into meshing engagement with a ring gear of an engine to perform startup of the engine.
2. Description of the Related Art
Starters having an intermediate gear of the type described are known as disclosed for example in Japanese Patent Application Publication JP 2002-180937 A1 (corresponding to U.S. Pat. No. 6,647,812). The disclosed starter includes an intermediate shaft supported on a housing at opposite ends thereof, an intermediate gear rotatably mounted on the intermediate shaft and axially movable thereon, and a pinion gear held in meshing engagement with the intermediate gear at all times. During startup of an engine, the intermediate gear is axially moved together with the pinion gear into meshing engagement with a ring gear of the engine.
To avoid unintentional removal from the housing, the intermediate shaft is retained to the housing by using a circlip or snap ring that is fitted in a groove on the intermediate shaft, or a pin that is press-fitted in the housing. However, due to the use of a snap ring, the first-mentioned retaining method renders the intermediate shaft and the housing complicated in construction and difficult to manufacture, leading to an increase in the manufacturing cost. The second-mentioned retaining method is also problematic in that due to the use of the pin press-fitted in the housing, detachment of the intermediate shaft from the housing is practically impossible and, hence, maintenance involving replacement of the gears inside the housing cannot be performed.